Filling orders from stored inventory requires at least three steps: locating the precise item in the storage facility, retrieving (or picking) the desired quantity of that item, and storing (or putting) the retrieved items in a designated container or receptacle. The basic steps may apply to a variety of situations in which items must be identified, selected, and distributed or placed in a second location. Frequently this process is generally described in terms of order fulfillment in a warehouse.
Storage in a facility may be viewed as a nested or hierarchical arrangement with bays arranged along aisles, shelves or storage containers located in or on a bay, and items located in or on a shelf. Thus, the location of a specific item, commonly referred to as a Stock Keeping Unit or SKU, would be an “address” in the storage facility comprising the aisle, the bay along that aisle, and a shelf, bin or container located in the bay. So long as a protocol exists to associate only one SKU with each unique combination of aisle, bay, and shelf, identification of a particular SKU is unnecessary to identify or characterize the item to be picked, since the address of the item is sufficient.
In an exclusively manual system, an employee receives an order for a specific item or group of items. Either by memory, which is subject to error, or by reference to a facility map or plan, the employee must identify the location of the item, go to that location, pick the required quantity of that item for the order, and place them in an appropriate receptacle. This process is repeated until a given order is filled, at which time the employee will return to a central point for subsequent packing or shipping of the items in the order. Multiple opportunities for errors exist, from misreading the storage facility location label, to selecting from an incorrect, but adjacent shelf or other storage receptacle, to picking the wrong quantity of the correct item, or to putting the correct items in an incorrect receptacle for subsequent packing or shipping. In addition, many separate orders may require the same item, but in an exclusively manual system, batch order picking is most commonly the exception, rather than the rule, resulting in significant inefficiencies associated with repeated trips to pick each order separately.
Technology has advanced beyond the exclusively manual system of pick and put. The evolution of computer technology and related electronic systems has played a significant part in this advancement. U.S. Pat. No. 3,739,339 issued to Hillhouse on Jun. 12, 1973 describes a system that is characteristic of the status of current pick and put technology for many warehouse-like situations.
In the '339 patent, a computer punch-card system is used in which the row by column punch matrix of the card represents the storage location of items, and quantities of the item to be picked may also be encoded. At least one card reader is wired to a computer. When a card is inserted into a card reader positioned on a bay or similar group of discrete storage units, the configuration of punches activates a light system such that the precise location of the item is indicated by an illuminated element, and the quantity to be selected is displayed in a centrally located, lighted display. The system also provides for a put-to-light process with a separate light system wired to individual containers or receptacles. Major deficiencies of this system include the requirement of hard wire communications of the light systems, communications through the card reader to a central computer, and the fact that overall efficiency and performance of the system degrades as the number of lights increases. The system has virtually no fault tolerance since failure of the central computer causes the entire system to fail.
Radio communications have been applied to inventory related, selection applications. U.S. Pat. No. 5,877,698 issued to Kusiner, et al. on Mar. 2, 1999 describes a system of radio transmitters positioned throughout a supermarket with mobile receivers positioned on shopping carts commonly used by customers. When a receiver is within a limited range of any specific transmitter, an exclusive link is established whereby the transmitter sends to the receiver a specific advertising message calling attention to a “bargain” product at a specific nearby location. The link is broken as the receiver moves out of range of the local transmitter, but may establish links with other transmitters throughout the facility.
U.S. Pat. No. 6,124,800 issued to Beard and Bunte on Sep. 26, 2000 discloses and claims a route delivery system utilizing both local area network and wide area network radio frequencies to communicate inventory data between an end delivery point (such as a vending machine) and a stocked delivery vehicle, and between the vehicle and a base office to minimize the number of actual visits a service person must make to deliver the necessary inventory items to a specific end point as well as to simplify routing of the delivery vehicle.
U.S. Pat. No. 5,505,473 issued to Radcliffe on Apr. 9, 1996 and U.S. Pat. No. 5,877,962, a divisionally related patent issued to Radcliffe on Mar. 2, 1999 describe and claim respectively a computer-based system to facilitate proper placement of articles picked by an attendant from inventory storage shelves and deposited in delivery containers mounted on a cart and a method for the practical utilization of the system. In addition, the system and related method include an optional beacon light system to indicate the location of inventory items to be picked or recovered. The system of the '473 patent and related method of the '962 patent depend on a single intelligent element or computer that must maintain constant two-way radio communication between a receiver/central control unit mounted on a cart and between the optional beacon system located on storage shelves. A scanner mounted on the cart is used to read codes on either the location or item to be picked to validate the designated pick.
Current technology includes warehouse management systems wherein given a request for any specific item, the system responds by identifying the specific storage location in the facility.
More recently, U.S. Pat. No. 6,775,588 issued to the present inventor describes and claims a unique distributed intelligence, wireless, light-directed pick/put system having a bi-directional, dual transmitter/receiver element in wired communication with a portable computer and in wired or wireless communication with put- and pick-controller units in which the portable computer translates order location data into light addresses that are communicated by wireless means to a pick-controller unit positioned on a storage bay and in electrical communication with a plurality of intelligent light assemblies. Each intelligent light assembly is positioned at a unique location such that in response to the communicated, translated, order location data, a specific intelligent light assembly is activated, illuminating a character display, thereby indicating the location and quantity of the SKU to be retrieved from that location. Further, the portable computer, the bi-directional, dual transmitter/receiver element, and put-controller unit are positioned on a mobile element that has a plurality of receptacles positioned on it, each receptacle having a unique, intelligent light assembly positioned near it and wired to the put-controller unit such that in response to translated location data communicated from the portable computer through the bi-directional, dual transmitter/receiver element and then through the put-controller unit, a character display is activated indicating the quantities of any retrieved SKU to be put into each of one or more indicated receptacles. Each intelligent light assembly of the '588 patent includes a momentary contact switch which provides the means by which the attendant indicates that the designated pick or put has been completed.
Most typically in the art, a momentary contact switch takes the form of a button to be pressed, although other types of switches may be employed. Most of such switches require at least one moving part that is subject to wear and, more importantly, are permanently fixed in a set location. Thus, it is difficult to reconfigure storage bay shelves to accommodate differing location sizes, as a fixed momentary contact switch must be associated with each shelf location. Similarly, it is difficult to reconfigure mobile unit locations accommodating differing location sizes, as a fixed momentary contact switch must be associated with each mobile unit location.
Further, the light directed pick/put system of the '588 patent is a complete distributed intelligence system in which picks only may be performed from stationary storage bay shelf locations, which include intelligent light assemblies controlled by a pick-controller, and stationary mobile unit locations, which include intelligent light assemblies controlled by a put-controller.